William thomas smith



(N0 Model.)

W. T. SMITH. DRIVING GEAR FOR VELOGIBEDBS.

No. 596,289. Patented Deo. 28,1897.

WILLIAM THOMAS SMITH, OF BOLTON, ENGLAND.

DRIVING-G EAR FOR VELOC-IPEDES.

SPECIFICATION forming part of Letters Patent No. 596,289, dated December 28, 1897. Application tiled August 31, 1896. Serial No. 604,372. (No model.)

To LZZ whom t may concern.:

Be it known that I, WILLIAM 'IrtoivrAsv SMITH, a subject of the Queen of Great Britcaster county, England, have invented certain new and Improved Driving-Gear for Velocipedes, of which the following description is a specification.'

In connection withA the driving-gear of ve-` cle more evenly throughout the entirety of\ each revolution of the crank without entailing the use of mechanism which will greatly add to the cost of production of the velocipede or which will engender other disadvantages is the object of this invention, and this object I attain by the employment of the mechanism illustrated by the accompanying sheets of drawings, in which- Figure l is a part sectional elevation of such a portion of a velocipede with my improved driving-gear applied thereto as is necessary to show how the latter may be put into use. Figs. 2 and 3 are similar views to Fig. l, but show in each case the employment of only one guide-pulley, the same being mounted to guide the chain in itsupper and lower paths,

`parts throughout the several views.

B indicates portions vof the velocipedes framework upon which the crank-spindle a and the spindle b of the velocipedes drivingwheel f are mounted, while c' are the cranks fixed to said spindle aand carrying the pedals dl On the spindle a I fix the well-known elliptical driving-wheel e, its larger diameter being at or about right angles to the radial arms or cranks c. Thus when these cranks c arein position for the rider to have the greatest power over them this power or force will at this time be transmitted by the chain g to the'driving-wheel f through the greater diameter of the elliptical wheel e in a manner vcircular driving-wheel is employed, I secure an ordinary sprocket-wheel h on the hub lof Ithe rear wheel, whileguideepulleys p p',

mounted to revolve on fixed bearings qq', are arranged in such positions relatively with the wheel c as to keep the chain gat its proper' tension, this position being clearly deiined as the center of the arc 3 4, (shown in broken lines, Fig. 1,) which bisects the horizontal planes in which the chain g travels and the vertical plane through the spindle a. Thus the slight variations in the tension of the chain g are represented by the distance that said arc 3 4 passes out of the vertical linel 2. In other Words, each of the Wheels p or p is so situated in its fixed location that although it delects the chain but slightly, if at all, when the longer radii of the elliptical wheel are at a right angle to the path of movement of the Wheel it materially deflects said chain when the shorter radii of the elliptical wheel are at a right angle to said path of movement. This will be evident by referring to Fig. 1, from which iigure it will be clear that if theguide-wheels Were omitted the chain would be very slack or loose when the ellip- However, when this ellipl tical 'Wheel is in the position indicated by full lines in said ligure. Again, I iind that one guide-wheel p, as shown by Fig. 2, or one, p', as shown by Fig. 5, is quite suicient to maintain the chain g in its proper positions on the wheels e h', and either or any of these devices may be employed when the wheel e has a circumference greater or less than twice that of the wheel 7L.

Having thus described the nature and object of my invention, what I consider new, and therefore claim, is-

l. In a velocipede, the combination of an elliptical driving chain-wheel, a concentric driven chain-Wheel, a chain connecting them, and a concentric guide-wheel mounted to re- IOO volve on iixed bearings, the outer portion of the periphery of the guide-Wheel being situated outside of a line drawn from the periphery of the concentric driven Wheel to the shorter radius of the elliptical Wheel, Whereby the path of movement of the chain is de- Iiected more or less according to Whether the shorter or the longer `radius respectively of the elliptical Wheel is at a substantial right angle to said path of movement.

2. In a velocipede, the combination of an elliptical driving chain-Wheel, a concentric driven chain-Wheel, a chain connecting them, and a pair of concentric guide-Wheels, one for each stretch of the chain and mounted to revolve on fixed bearings, each of said guide- Wheels having the outer portion of its periphery situated outside of aline drawn from the periphery of the concentric driven wheel to the shorter radius of the elliptical Wheel, whereby the path of movement of the chain is deflected more orless according to whether the shorter or the longer radii respectively of the elliptical Wheel are at a substantial right angle to said path of movement.

XVILLIAM THOMAS SWITIT.

lVitnesseS:

JOHN WHITEHEAD, SAMUEL HEY. 

